1. Field of the Invention
The invention relates to a cylinder head for an internal combustion engine with pump/nozzle units, there being provided on the cylinder head at least one bearing block with a bearing half for a camshaft and with a bearing half for a rocker arm shaft for rocker arms for actuating the pump/nozzle unit.
2. Discussion of the Prior Art
A generic cylinder head is known from German reference DE 42 32 783 A1. A pump/nozzle unit is fastened to the cylinder head via a rocker arm shaft and bearing blocks for the rocker arm shaft, so that a fastening flange is dispensed with and the unit itself therefore projects only slightly laterally. German reference 196 34 541 A1 also discloses a method for producing a bearing arrangement of this type.
It is known from German reference 31 46 875 C2 to provide, in a rocker arm shaft itself, a lubricant path for supplying lubricant for a bearing part of the rocker arm. Furthermore, a bearing bed has formed in it a groove communicating with an annular gap which is located in a fastening screw and via which lubricant feed takes place. In order to reach a plurality of recesses arranged at a distance from one another and intended for supplying lubricant to different components, this groove must be produced with a sheet-like chamber-shaped extent. Due to this sheet-like character and due to a plurality of recesses branching off from the groove in order to feed lubricant to a plurality of components, the exact lubricant flow and the lubricant quantity conveyed in each case to the various points or the respective throughput cannot be predetermined accurately. Another disadvantage is that additional sealing measures have to be provided in the region of the screw surrounded by the annular gap, in order to prevent lubricant from escaping even when it is under high pressure.
The object on which the present invention is based is to provide an improved cylinder head of the above-mentioned type, in which the operating reliability of the structural unit consisting of camshaft, rocker arm shaft, rocker arms, pump/nozzle unit and charge cycle valves is increased in a simple way.
For this purpose, there is provision, according to the invention, for providing a first separate lubricant supply duct in the cylinder head and a second separate lubricant supply duct in the bearing block, a first end of the second lubricant supply duct being connected to the first lubricant supply duct and a second end of the second lubricant supply duct ending open in a bearing face for the rocker arm shaft.
The advantage of this is that a sufficient feed of lubricant to the rocker arm shaft is ensured in a simple manner, the lubricant feed being brought about without additional measures, at the same time as the mounting of the bearing block, by means of a connection of the first and second lubricant supply ducts. In contrast to an above-mentioned groove in the bearing bed, the second lubricant supply duct makes it possible to guide the lubricant in a directed manner to an exactly predetermined point, specifically the second end of the second lubricant supply duct, with a lubricant throughput which is exactly predetermined, inter alia, by a cross section of the lubricant supply duct, since there is no distribution over a large area, as in a groove, but a directed guidance of the lubricant in the duct. Furthermore, the arrangement of separate lubricant supply ducts avoids the need for a combination of screw bores in this region, so that additional sealing measures in the region of a screw orifice used as a lubricant path are unnecessary.
In order to supply the first lubricant supply duct with lubricant, the first duct is advantageously connected to a lubricant gallery.
A simple combination of only two different components in order to implement an arrangement for the actuation of pump/nozzle units during the production of internal combustion engines having different numbers of cylinders is achieved in that a rocker arm shaft is provided for the mounting of rocker arms for respective pump/nozzle units for two cylinders and a rocker arm shaft is provided for the mounting of rocker levers for respective pump/nozzle units for three cylinders. By an appropriate combination of only these two rocker arm shafts, internal combustion engines can be equipped with any desired number of cylinders, in particular with two, three, four, five, six, eight or twelve cylinders.
For the supply of lubricant to the camshaft, in a particularly advantageous way at least one third separate lubricant supply duct is formed in the cylinder head and is connected to a lubricant gallery or to the first lubricant supply duct and ends open in a bearing face of the camshaft in the cylinder head.
In order to supply lubricant to a secondary assembly in a simple way, furthermore, in a preferred embodiment of a cylinder head according to the invention, at least one fourth lubricant supply duct is formed in the cylinder head.
At the same time, a particularly simple arrangement which is particularly cost-effective to produce is achieved in that the fourth lubricant supply duct is connected to the oil gallery. The secondary assembly is, in this case, preferably a blower, an alternator and/or a water pump.
The rocker arms for the actuation of respective pump/nozzle units are expediently arranged between bearing blocks. This advantageously reduces a construction space taken up by the arrangement.
The lubricant is expediently oil.
For an optimum supply of lubricant to the rocker arm of the pump/nozzle unit, advantageously a fifth lubricant supply duct is formed in the rocker arm shaft and is connected to the second lubricant supply duct and conducts lubricant to a bearing point of the rocker arm of the pump/nozzle unit.